This invention relates generally to an apparatus for providing a support deck for a mattress or a seat. The support deck of this invention is particularly suitable for, but not limited to, use in sofa beds. In the past, sofa bed mattress decks have been made with metal link fabrics or polypropylene which are attached to an outside frame with hooks or helical connectors. The link fabric decks have an inherent flaw in that they are comprised of a grid of wires which are free to pivot or yield, thereby offering little resistance when a person sits or rests on the unfolded sofa bed. This yielding effect is known in the bedding industry as xe2x80x9chammockingxe2x80x9d.
Sofa bed decks which are made from polypropylene likewise suffer from the same inherent flaw in that they consist of a canvas-type material attached to a frame with hooks or helical connectors which are insufficiently resilient to provide proper support for a person sitting, reclining or resting on the sofa bed.
Another problem associated with currently existing decks commonly referred to in the industry as xe2x80x9ccrowningxe2x80x9d. Crowning occurs when the sofa bed mattress, after having been folded and recessed back into the sofa, pushes upward against the sofa bed deck to cause a bulge. This crowning effect is particularly a problem with thick mattresses. The bulge is generated because the sofa bed deck is not sufficiently strong enough to resist and contain the folded and compacted mattress.
The bulge created by the crowning of the mattress inhibits the seat cushions from laying flat on the sofa; a condition referred to in the industry as cushion xe2x80x9csmilingxe2x80x9d. Sitting on a sofa with xe2x80x9csmilingxe2x80x9d cushions is unpleasant in that one teeters back and forth while sitting on the firm mattress bulge.
One proposed solution to these problems has been to manufacture a deck from serially interlocked metallic wire-like link members interconnected by metal rectangular plate-like members such that the resulting deck resists upward force when in a horizontal configuration, but yields to downward force under the weight of one sitting or reclining thereon. Problems associated with this proposed solution include great difficulty in manufacturing the various component parts and, therefore, increased expense in manufacturing a sofa bed or the like with such a deck structure. This is particularly troublesome in the highly competitive bedding and mattress industry in which production and manufacturing costs often distinguish the successful designs from the many comparable alternatives.
An objective of the this invention is to provide an improved deck structure for use in sofa beds or other seating or bedding support systems.
A further objective is to provide a sofa bed mattress deck that eliminates the problems of xe2x80x9chammocking,xe2x80x9d xe2x80x9ccrowningxe2x80x9d and cushion xe2x80x9csmilingxe2x80x9d.
A further objective is to provide a sofa bed mattress deck that can accommodate a thicker sofa bed mattress while providing for neat and compact storage or folding of the mattress into the sofa bed.
A further objective is to provide a sofa bed mattress deck that will achieve the above objectives and yet is relatively inexpensive to manufacture.
These objectives are obtained by a support deck attached to a sofa bed frame. The deck is formed from a series of serially hinged links joined together such that when the deck is pushed from the bottom side it resists and maintains its flat surface (i.e. it is in a locked position). However, when the deck is pushed or forced from the top side it yields or bows. As a result, when the sofa bed is unfolded, a firm mattress deck is provided that contours to the user""s body without excessive sagging. When folded and stored within the sofa bed, the deck provides a flat surface upon which the sofa bed cushions can be placed without smiling or bulging. In this folded condition, the mattress is pushing upward and outward against the side of the deck that is in a locked position and thereby resists the upward force of the mattress.
The support provided to a person sitting or resting on the sofa bed in the sofa configuration simulates that of a standard sofa with a spring seat. This is due to the fact that the deck, while locked against upward movement, will yield in downward movement in response to a person""s weight.